Britain will vote to leave the EU because people are "pouring in all over the place" as a result of 'crazy' levels of immigration, Donald Trump has predicted.

The front-runner for the Republican presidential nomination and billionaire tycoon also hit out at Boris Johnson's claim that his comments calling for a ban on Muslims entering the United States made him "unfit" to be President.

In an interview with ITV's Good Morning Britain, he said there was "unrest" in the UK and insisted "thousands and thousands" of Britons backed his controversial comments about Muslims.

Mr Trump said: "I think that Britain will separate from the EU. I think that maybe it's time, especially in light of what's happened with the craziness that is going on with immigration, with people pouring in all over the place I think that Britain will end up separating from the EU.

The Prime Minister has branded Mr Trump's comments “divisive, stupid and wrong” but rejected calls for Trump to be barred from visiting the UK.

Donald Trump, left, and Boris Johnson

Speaking in December Mr Johnson, said: "I think Donald Trump is clearly out of his mind if he thinks that's a sensible way to proceed, to ban people going to the United States in that way, or to any country.

"I think he’s betraying a quite stupefying ignorance that makes him frankly unfit to hold the office of President of the United States."

Mr Trump said the London Mayor "looks like a good character and probably a nice guy.

British Muslims

"When I talked about the Muslim ban, he was very strong against me. He said like they have no problems in London at all but I was written letters and phone calls talking about London and talking about the fact that I was right."

Mr Trump said there had been widespread opposition to calls for him to be banned.

"There was such opposition from people that live in Great Britain, in the UK generally, in fact all over Europe, the people were incensed at the concept of me being banned for speaking really what they said was the truth.

"And, as you know, that ban went nowhere, it shouldn't have gone anywhere, it was a disgraceful thing but it went nowhere, but a lot of people - and I mean thousands and thousands of people - were tweeting saying you're right, you're right, Mr Trump, you are right, and so I don't know what's going on over there but I can tell you there is some unrest."